1. Field of the Invention
This invention relates generally to assistive mobility devices and more particularly to a collapsible wheeled weight bearing walker or rollator.
2. Description of the Related Art
Assistive mobility devices, including walkers rollators, are well known in the art as useful means for reducing the disadvantages of mobility impairment suffered for many different reasons by many people, permitting more efficient ambulation over distance and thereby increased independence and improved life quality. Data from the National Long Term Care Survey suggests that increased use of assistive technology may have helped reduce disability at older ages [Manton, et al., “Changes in the Use of Personal Assistance and Special Equipment from 1982 to 1989: Results from the 1952 and 1989 NLTCS,” Gerontologist 33(2):168-76 (April 1993)]. As life expectancy' increases over the decades the mobility-impaired population increases much faster than the general population [LaPlante et al., “Demographics and Trends in Wheeled Mobility Equipment Use and Accessibility in the Community,” Assistive Technology, 22, 3-17, (2010)]. Accordingly, there has long been a growing demand for improved mobility assistance devices adaptable for improving ambulation for mobility-limited persons.
Martins et al. [Martins et al., Assistive Mobility Devices focusing on Smart Walkers: Classification and Review, Robotics and Autonomous Systems 60 (4), April 2012, pp. 548-562] classifies mobility assistance devices into the alternative devices intended for those with total loss of independent mobility (wheelchairs or autonomous powered vehicles) and assistive or augmentative devices for those with residual mobility capacity (prostheses, crutches, canes and walkers). For several reasons, most impaired individuals prefer to avoid the alternative devices associated with total incapacity. Similarly, the rehabilitation profession strongly prefers the assistive devices, which may be used for physical therapy and as mobility-training devices. Accordingly, there has long been a growing demand for improved assistive devices adapted for use by the less disabled who otherwise cannot move independently with existing assistive devices and are forced to rely on alternative devices such as wheelchairs and powered scooters.
As one type of assistive device, many wheeled walkers or rollators have been developed and are available on the market for the benefit of mobility impaired individual. U.S. Pat. No. 7,108,004 issued to Cowie et al. discloses a typical rollator that has a right side frame and a left side frame supported by front wheels and rear wheels, a seat extended between the two side frames for the rollator user to sit on, and two handles extended from the upper structures of the side frames for grasping by the user. The rollator, including the seat, is foldable from side-to-side. However, such an assistive device has many well-known disadvantages. One notable disadvantage is that the user needs to extend her of his hands downward to grasp the handles to support her or his body weight, so relatively significant hand and arm strength is needed to operate and maneuver the device. Over the time in this type of walker, a user may develop a stooping or a forward leaning posture to avoid a hobbled gait. A stooping posture stresses the user's back and arms, compresses internal organs including heart and lung, and restrains circulations. Moreover, such posture may increase the risk of tipping forward when encountering terrain obstacles. A seat in a walker, as shown in U.S. Pat. No. 7,108,004, has the benefit of allowing the user to sit down for resting. But the disclosed seat constructed between the right and left side frames blocks the space available inside the walker footprint. Consequently, the user is forced to step behind the walker footprint to avoid kicking into the seat. This also encourages a stooping posture.
There has long been a clearly-felt need in the art for improved assistive devices to better help those who suffer from mobility impairment. The commonly-assigned U.S. Pat. No. 9,585,807 issued to Fellingham et al. discloses an upright wheeled walker with armrests that support sufficient user upper-body weight to facilitate a natural upright gait. The wheeled walker has two side frames that may be collapsed and folded and two side upper supports that may be lowered, to reduce the walker width and height for storage and transportation. A large polygonal space is created inside the walker device to prevent the user from kicking into the walker structure. With improved walking posture, the user can walk longer and get more physical exercises, thereby promoting circulation and overall health, and therapeutic effects for certain diseases, or after surgery or injury. The wheeled walker apparatus disclosed in U.S. Pat. No. 9,585,807 has improved lateral and longitudinal stability and therefore better safety for the user. This is accomplished by improving frame and connection sturdiness. The result is reduced wobbling of the upper support structure.
However, the wheeled walker of U.S. Pat. No. 9,585,807 does not include a seat. After walking for a distance when the user feels tired and wants to sit down to take a rest, the device does not provide such a seat. U.S. Pat. No. 9,744,094 issued to Liu et al. discloses a walker apparatus having a seat connected to the upright side frames. This seat is similar to the one disclosed in U.S. Pat. No. 7,108,004 discussed above, and is of a typical type provided in walkers known to practitioners. Disadvantageously, when the space inside the walker footprint is occupied by such a seat, the user is obliged to step behind the walker footprint and to lean over to reach the walker handles, thus an unhealthy walking posture.
This walker footprint problem is resolved by the collapsible combination chair/walker disclosed in U.S. Pat. No. 5,741,020 issued to Harroun. The combination chair/walker includes a removable seat that is detachably mounted on intermediate level side rails. Removing the seat leaves ample space inside the walker footprint for walking and standing. Disadvantageously, such a seat is not permanently attached to the walker and the necessary mounting and unmounting process is complicated and tedious. Moreover, the seat member may get lost during use, storage and transportation. U.S. Pat. No. 9,662,264 issued to Jacobs discloses a front entry upright walker that includes a seat that is connected with the frame to pivot between a deployed horizontal positon where a user may sit upon and a stowed vertical position to allow a user to walk within the space. However, the disclosed walker structure has a weak connection between the left to right side frames that cannot provide a sturdy and stable walker frame during walking when the seat is flipped up at its stowed position.
Other improvements have been proposed for wheeled walkers. For example, it has been proposed to provide a combination assistive-alterative device for impaired users who have limited capability to operate a walker independently. Such a user may benefit from a walker for exercise or physical therapy, but must be transported, in a transport chair or wheelchair by a helper after walking for awhile. U.S. Pat. No. 5,137,102 issued to Houston discloses a powered wheelchair that provides a movable seat to make space and allow the user to stand up inside the device footprint. Since this device does not allow the user to walk or stand up on the ground, its therapeutic effect is limited. And, the electrical components and complicated mechanisms of the device make it un-foldable, heavy and not easy to transport in a car, and costly to purchase. U.S. Application Pub. No. US 20170209319 by Fawcett et al. discloses an elevating chair walker that has a seat elevated by a parallelogram power unit to lower and higher positions and is convertible between a wider seat to sit and a narrower saddle to ride. The device allows the user to stroll, stride and coast, and relatively easily sit down and rise up, all in a functionally equipoised and weightless condition. Nevertheless, the walker chair surrounds the user from behind, so the user essentially pulls the device along when using it. Accordingly, such a device may be a good choice for one with limited mobility to use in or around the residence, for example, to walk or ride inside a house and to do chores and activities. But it does not provide benefits for outdoor use because one with limited mobility and balance needs the walker frame and support in front to lean on and provide a sense of security.
Other improvements have been proposed for individuals who are impaired or paralyzed on one side of the body because of health conditions such as stroke or neurological disorder. Such a user cannot control the walking direction of a wheeled walker. Thus, it would be advantageous to improve the walker device to be configured so that all wheels move in straight
Ease of use improvements have also been proposed. For example, walker or rollator devices usually have height adjustment mechanisms to fit individuals of different height. When a user gets a walker, however, he or she will try the walker including setting a preferred height for him or her to use. Since the user's height changes little over time, theoretically the height adjustment should be done only once. However, there will be needs time and again to collapse the walker device to its minimal size, including the smallest height, for storage and transportation purpose. This means that the device will need to be opened up for use, and height setting will need to be repeated time after time. It would be advantageous, therefore, if the preferred height, after being set, can be kept or memorized by a specially designed device.
These unresolved problem and deficiencies are clearly felt in the art and are solved by this invention in the manner described below.